Electric radio organ



Nbv. 13, 1934. E CQUPLEUX r AL 1,980,912

' ELECTRIC RADIO ORGAN Filed Jan. 21, 1953 2 Sheets-Sheet l "Ti? A JF fmnZorJ. W

@ awn/m NOV. 13, 1934. E. E CQUPLEUX ET AL 1,980,912

ELECTRIC RADIO ORGAN Filed Jan. 21, 1955 2 Sheets-Sheet 2 jla 'FS'F I w, M

fur/anions Edouaralfi', a Wleux? Patented Nov. 13, 1934 PATENT OFFICE ELECTRIC RADIO ORGAN Edouard Eloi Coupleux, Tourcoing, and Joseph Armand Givelet, Paris, France Application January 21, 1933, Serial No. 652,868 In France January 28, 1932 9Claims.

It is well known that it is possible to obtain the production of notes in a polyphonic instrument by means of an oscillating system based on the property of electron valves, glow lamps,

' etc.

In order to obtain polyphony and to harmoniously combine sounds it is necessary to eliminate the beats resulting from interferences between the notes, the harmonics, etc. This result is obm tained by means of filters and particular arrangements which are described in our Patent No. 1,905,996 and our copending application Serial Number 638,032, filed October th, 1932.

The object of the present invention is to pro- 15 vide a novel and simplified construction of a radio-electric organ and to render it easier to obtain the different required timbres or stops in such a manner as to imitate all existing instruments, also to obtain new timbres, and to 9 combine all these timbres together in such a manner as to obtain a musical instrument meeting all these desiderata.

In order to obtain this result the oscillating circuit corresponding with each note is connected with a common combining transformer with a number of primary windings and a single secondary winding according to arrangements already known, and choke coils are inserted in series. To the single secondary of the common output transformer, there are connected in series a number of windings forming the primaries of individual transformers, the secondaries of which individual transformers are each connected to loud speakers through the intermediary of systems of filters, transformers, and the like, the filters being suitably calculated in such a manner as to give each of the loud speakers 9. well defined special timbre or pitch.

In modifications of the system the connection between the plate and the primaries in series,

referred to above, is eifected through the medium of a condenser or an impedance, the choke coils being as previously, inserted in the positive plate battery leads, and the condenser or 5 impedance are connected to one side of the individual primaries in series of which the other side is connected to a return terminal.

In order to avoid variations in impedance which are produced when one of the loud speakers remahis unused, diflerent arrangements are resorted to as it is insumcient to simply provide a switch in such a manner as to short-circuit the primary or the corresponding secondary itself of the transformer finally supplying the loud speaker through a filter, amplifier etc. It is preferable to arrange a short-circuiting switch after the amplifier. There may, however, be arranged in series with each individual primary, 9. suitable resistance, a two-point electromagnetic switch capable of short-circuiting the primary and thus bringing into circuit an adjustable compensating impedance, or vice versa, the twopoint switch being actuated by an electromagnet. Further, it is also possible to short-circuit the secondary or to have a loose coupling for the individual transformer. Also, with an ordinary individual transformer there may be applied a suitable grid bias which stops oscillation, and it is also possible to render the valve inactive by interrupting the plate current.

A small number of valves is necessary for the radiophonic organ of the present invention owing to the fact that each valve can be controlled simultaneously by a number of different key-boards. An ordinary organ usually comprises several key-boards. For this purpose the valve is allowed to oscillate continuously; but the output transformer used therewith has as many secondaries as there are key-boards, each secondary being connected to the input valve of 30 a corresponding amplifier between the grid and filament. It is, therefore, connected to a circuit of high resistance and low current consumption in such a manner that when a key is pressed, for actuating a relay energizingthe secondary and also its amplifier, the operation of the oscillating valve is not modified and no energy is absorbed. The output produced is therefore multiplied by the number of key-boards thus actuated. The coupling may be effected electromagnetically or electrostatically.

The accompanying drawings show, by way of example, methods and means for carrying out the present invention. In these drawings:

Fig. 1 indicates, diagrammatically, an arrangement involving the principle of the invention.

Fig. 2 is a modification with condensers.

Fig. 3 is'a modification with'impedances.

Fig. 4 shows details of operation of short-circuit devices, either on the primaries or on the secondaries of individual transformers.

Fig. 5 shows a short-circuit provided after an amplifier.

Fig. 6 shows the electromagnetic two-point switch and a compensating resistance.

Fig. 7 is a circuit diagram of a valve for two key-boards with electromagnetic coupling.

Fig. 8 is a modification of the preceding diagram with electrostatic coupling.

As will be seen in Fig. 1, each valve L is pro-,

vided with an oscillating circuit 0. The plate is connected to 'a choke coil 0 which leads to a primary p of a transformer T with a single secondary winding S, like arrangements being provided for coils c, 0" etc.

To the secondary S are connected, in series, primaries a, a, a" etc. of transformers t, t, t" etc.

The secondaries of the transformers t, t, t" etc. are each provided with a filter equipment I, 1 etc., an amplifier A, A, A, etc., filters f1, f1, f1" etc. and a loud speaker D, D, D".

By suitably calculating the filters f etc. and f1 etc., there is obtained in each loud speaker or reproducer D a musical sound output with a suitable timbre.

In Fig. 2 the plate circuit of each of the valves is provided with a choke coil which is connected to the positive terminal of the plate potential as in Fig. 1, and in parallel with each choke coil there is arranged a condenser such as g, g, g" which is connected to the primaries a, a, a" etc. arranged in series and connected to a return terminal M. As in Fig. 1, for each primary winding as a, there is provided the filter as f, the amplifier as A, and the loud speaker as D. The use of the condensers prevents the choke coils from preventing completely the passage of high harmonics which may cause disadvantages by blocking the notes in such a manner that nothing is obtained in, for example, the primary windings of transformers t, t, etc.

In Fig. 3 the condensers are replaced by impedances r, r, 1'" etc. which are naturally suitably calculated so as to allow the oscillations to pass and especially the harmonics of high frequency.

If it is desired to put one of the loud speakers D temporarily out of service it is possible, as shown in Fig. 4, to short-circuit either the secondary of a transformer, by means of a contact (p) or the whole or a portion of the primary, by means of another contact (1)). Nevertheless this has the disadvantage or changing the total impedance of the circuit inthe individual primary and it is preferable to adopt the device of Fig. 5 in which a short-circuiting contact 1) is interposed after the amplifier A. As previously stated it is also possible to change the grid bias, or interrupt the plate current, etc.

Fig. 6 shows an arrangement wherein the shortcircuited primary winding may, when desired, be replaced by a compensating resistance 1' provided with an adjustable slide which enables this resistance to be altered in a precise manner for compensating the short-circuited primary a.

The arrangement may be carried out by means of a contact blade 1 hinged at Z and actuated by an electromagnet E. When the blade comes into contact with K2, which is its normal position, the compensating resistance 1' is short-circuited and the transformer t is energized' If the blade is in contact with K1 the primary a is short-circuited and the resistance r then is inserted into the main circuit in such a manner as not to change the total impedance of the said circuit.

The portion of the resistance which is not used is automatically short-circuited since the active part of the resistance, by action of the slide, gives the exact desired resistance for balancing the impedance.

Fig. '7 shows a valve L which serves two octaves but may serve a greater number. This valve oscillates continuously. The condenser 11, in dotted lines, enables the oscillating current to pass in spite of the inductance of the primary of the transformer 12. This transformer has a number of secondaries equal to that of the key-boards of the instrument. Each secondary has an equipment composed of a key such as F with a contact blade such as 1 for passing current to an electromagnet 2. When the magnet is excited the core 2 brings into action, by reason of a contact plate 3, the corresponding secondary of a connecting transformer t with'the amplifier A, the filter f and the loud speaker D. (The transformer t-is not absolutely necessary.)

The operation will be apparent which is caused by depressing key F, the electromagnet 2 thus being energized.

Fig. 8 shows a modification with electrostatic coupling. The elements shown in the dotted rectangle, which are used in other arrangements for controlling the operation of the tube by shortcircuiting the grid winding, are omitted. The electrostatic coupling is used instead of transformer coupling. The valve L is kept in constant oscillation by omitting the contacts 5 and 5', the electromagne't '7, and the contact 3 which when .at rest short-circuits the oscillating circuit 0. There only remains on the key F a single contact 6 which permits of energizing an electromagnet 8 which attracts a plate 9 closing the circuit of the note. To the same valve may be connected the corresponding notes of the other key-boards as will be seen as shown by the key F and it is possible to connect still others on the same valve. The output of the valve is delivered to condensers such as 10 each of them serving an assembly of transformer primaries a, a, a" in series, each secondary being provided as above with its assemblage of amplifier, filter and loud speaker. The action of the condenser 10 is to allow high frequency currents to pass which the inductances on the contrary, have the tendency to choke.

What we claim is:-

l. Improvements in radio-electric organs, with a valve of three electrodes, an oscillating circuit with this valve, means for bringing the oscillating circuit into operation, a transformer with multiple primary windings and a single secondary winding, choke coils in the plate circuit of each of the valves, windings in series in the secondary of the general transformer, individual transformers having as primaries the said windings, filters placed in the secondary of the transformer, amplifiers connected to these filters, a loud speaker mounted on each amplifier.

2. Improvements in radio-electric organs, with Y a valve of three electrodes, an oscillating circuit with this valve, means for bringing the oscillating circuit into operation, a transformer with multiple primary windings and a single secondary winding, choke coils in the plate circuit of each of the valves, windings in series in the secondary of the general transformer, individual transformers having as primaries the said windings, filters placed in the secondary of the transformer, amplifiers connected to these filters, a loud speaker mounted on each amplifier, a capacity connect- 14o ing the plate of each valve to the primaries in series of the transformers, a common return wire branched on the choke coils. I

3. Improvements in radio-electric organs, with a valve of three electrodes, an oscillating circuit with this valve, means for bringing the oscillating circuit into operation, a transformer with multi' ple primary windings and a single secondary winding, choke coils in the plate circuit of each of the valves, windings in series in the secondary 159 of the general transformer, individual transformers having as primaries the said windings, filters placed in the secondary of the transformer, ampliflers connected to these filters, a loud speaker mounted on each amplifier, an impedance coil between the plate of each valve and the primaries in series of the transformers, a common'return wire branched on the choke coils.

4. In an electric organ, a plurality of electron tube oscillators, an individual grid circuit and an individual plate circuit respectively for each of said oscillators, a common source of plate potential for said oscillators, a plurality of individual choke coils connected respectively in series between the plate of each of said oscillators and the positive terminal of said source of plate potential, a plurality of output units each comprising means for converting electrical energy into sound, and means for maintaining mutual electrical relationship between the plate circuit of each of said oscillators and the input circuit of each of said output units for transferring electrical energy from said plate circuits to said output units. 7

5. In an electric organ, a plurality of electron tube oscillators, an individual grid circuit and an individual plate circuit respectively for each of said oscillators, a common source of plate potential for said oscillators, a plurality of individual choke coils connected respectively in series between the plate of each of said oscillators and the positive terminal of said source of plate potential, a plurality of output units each comprising individual frequency control filters and individual means for converting electrical energy into sound, and means for maintaining mutual electrical relationship between the plate circuit of each of said oscillators and the input circuit of each of said output units for transferring electrical energy from said plate circuits to said output units.

6. In an electric organ, a plurality of electron tube oscillators, an individual grid circuit and an individual plate circuit respectively for each of said oscillators, a common source of plate potential for said oscillators, a plurality of individual choke coils connected respectively in series between the plate of each of said oscillators and the positive terminal of said source of plate potential, a plurality of output units each comprising means for converting electrical energy into sound, and a plurality of individual means for maintaining mutual electrical relationship between the plate circuit of each of said oscillators and the input circuit of each of said output units for transferring electrical energy from said plate circuits to said output units.

7. In an electric organ, a plurality of electron tube oscillators, an individual grid circuit and an individual plate circuit respectively for each of said oscillators, a common source of plate potential for said oscillators, a plurality of individual choke coils connected respectively in series between the plate of each of said oscillators and the positive terminal of said source of plate potential, a plurality of output units each comprising means for converting electrical energy into sound, and a plurality of individual capacities for electrically coupling the plate circuit of each of said oscillators to the input circuit of each of said output units for transferring electrical energy from said plate circuits to said output units.

8. In an electric organ, a plurality of electron tube oscillators, an individual grid circuit and an individual plate circuit respectively for each of said oscillators, a common source of plate potential for said oscillators, a plurality of indi vidual choke coils connected respectively in series between the plate of each of said oscillators and the positive terminal of said source of plate potential, a plurality of output units each comprising means for converting electrical energy into sound, and a plurality of individual inductances for electrically coupling the plate circuit of each of said oscillators to the input circuit of each of said output units for transferring electrical energy from said plate circuits to said output units.

9. In an electric organ, a plurality of electron tube oscillators, an individual grid circuit and an individual plate circuit respectively for each of said oscillators, a common source of plate potential for said oscillators, a plurality of individual choke coils connected respectively in series between the plate of each of said oscillators and the positive terminal of said source of plate potential, a plurality of output units each comprising individual frequency control filters and individual means for converting electrical energy into sound, and a plurality of individual capacities for electrically coupling the plate circuit of each of said oscillators to the input circuit of each of said output units for transferring electrical energy from said plate circuits to said output units.

JOSEPH ARMAND GIVELET. EDOUARD ELOI COUPLEUX. 

